Wildlife laws are enforced by state and federal agencies, usually known as wildlife departments or fish and game commissions. In the United States, principal responsibility for laws protecting migratory species and threatened and endangered species rests with the U.S. Fish and Wildlife Service.

Various nongovernmental organizations (NGOs) have grown in membership and influence since the 1960s. NGOs include private conservation groups such as the National Audubon Society, the National Wildlife Federation, and the World Wildlife Fund. Although they have no direct legal powers, NGOs have achieved considerable influence over wildlife management through fund raising, lobbying, and other kinds of political action, as well as by filing lawsuits concerning wildlife-related issues.

Depletion of native wildlife during the late nineteenth century in the United States and Canada led to passage of federal and state laws regulating the harvest and possession of resident species. Congress passed the Lacey...